BERLIN (Reuters) - A senior conservative lawmaker on Tuesday told Germany’s Social Democrats they would jeopardise a hard-fought coalition agreement if they went overboard with spending plans for Europe.

Ralph Brinkhaus, deputy leader of the conservatives in parliament, said conservatives would insist on averting new government debt, and planned to examine any European spending plans very carefully.

Conservatives are still smarting from Chancellor Angela Merkel’s decision to let an SPD politician serve as finance minister, a job long held by budget hawk Wolfgang Schaeuble, who was known for his focus on budgetary discipline.

“I don’t see the European part of the coalition agreement as a blank cheque,” Brinkaus told Die Welt newspaper. “If someone starts to give away Germany, we won’t support that.”

Social Democrat Olaf Scholz, who is expected to become finance minister, last month said the SPD would preserve Schaeuble’s balanced budget policy, but Germany should not dictate economic policies to its euro zone partners.

Merkel on Monday welcomed a majority vote by SPD members to back the coalition agreement, and vowed to press on with joint efforts with France on European reforms and other issues such as trade policy.

The SPD vote result brought relief to German businesses and European capitals, which say the euro zone would benefit from Merkel being able to partner with French President Emmanuel Macron on ambitious plans to reform the single currency bloc.

Brinkhaus’s comments underscored tensions between the centre-left SPD and the conservative blocs, which are both under pressure to differentiate themselves more in the next “grand coalition” after big losses in the September national election.

While they have agreed broad policy outlines, the two blocs must still work out disputes on implementation of immigration, car missions, labour rules and welfare.

Brinkhaus acknowledged that Germany would face increased responsibility for Europe given Britain’s planned departure from the economic bloc and a result of increased EU security needs, but said the EU also needed to find savings in its coffers.

“We want a common European defence policy. We want common protection of the external borders. None of that happens for free,” he told the newspaper.

“But we think it’s important that the European Commission uses existing funds for these missions,” he said. “There are still many savings to be had in the European budget.”